Optical pickup device and optical disc drive apparatus

Abstract

The present invention provides an optical pickup device employing a disc protector that includes a plurality of first protrusions and at least one second protrusion disposed on the lens holder, wherein the first protrusions are formed by applying a first adhesive to a plurality of areas of a top surface of the lens holder, wherein the first protrusions are arranged at different locations in the tracking direction such that the objective lens is sandwiched between the first protrusions, wherein the at least one second protrusion protrudes is formed by applying a second adhesive to at least one area of the top surface of the lens holder, and wherein tips of the first protrusions are closer to the optical disc than a tip of the at least one second protrusion.

Description

[0001]The present application claims priority from Japanese application JP2006-227529 filed on Aug. 24, 2006, the content of which is hereby incorporated by reference into this application.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to thin optical pickup devices (sometimes referred to as slim or ultra-slim optical pickup devices) for writing to and reading from an optical disc such as a CD (compact disc), DVD (digital versatile disc), etc., and relates to optical disc drive apparatuses incorporating such a thin optical pickup device. The invention also relates to optical pickup devices for writing to and reading from an optical recording medium such as a Blu-ray disc (for use in a blue semiconductor laser), HD-DVD, etc., and relates to optical disc drive apparatuses incorporating such an optical pickup device.[0004]2. Description of the Related Art[0005]The following describes the inner workings of an optical pickup device for writi...

AI Technical Summary

Benefits of technology

[0014]The present invention has been devised to solve the above problems. It is, therefore, an object of the present invention to provide a low cost, high reliability optical pickup device employing a disc protector that is formed of only inexpensive adhesives but that has equal or higher functionality than conventional disc protectors and is easy to fabricate. Another object of the present invention is to provide an optical disc drive apparatus incorporating such an optical pickup device.

[0020]The present invention enables one to easily form a disc protector (or contact preventing member) of an optical pickup device at low coat. The disc protector prevents damage to the objective lens and the optical disc when the focus servo system of the actuator portion does not function as intended or when a strong force is applied to the optical pickup device. This allows a significant reduction in the cost of the optical pickup device and hence the cost of optical disc drive apparatuses incorporating such an optical pickup device.

Problems solved by technology

Although the above conventional optical pickup devices have satisfactory performance, it is very difficult to assemble them, that is, their manufacture requires an increased number of processes.

Further, a special resin material must be used to form the protector member(s), resulting in increased cost.

However, adhesives have tackiness and have a high friction coefficient and poor surface slipperiness, as compared to POM and the special fluorine-based resin material described above (which have a low friction coefficient and very high surface slipperiness).

In this case, however, the adhesive still has a higher friction coefficient than the above special resins (which have a low friction coefficient and very high surface slipperiness).

Furthermore, the high hardness of the adhesive (or lens protector) may result in damage to the surface of the optical disc.

In such a case, however, the adhesive has increased tackiness and hence an increased friction coefficient, resulting in an increase in the frictional force on the adhered portion.

Furthermore, if a shock is imparted to the optical pickup device, the lens protector may collide with the lens holder or the objective lens since it has a reduced hardness (as described above), resulting in damage to the lens holder or the objective lens.

That is, unlike the above molding resins, no single adhesive can provide both the required surface slipperiness and the required characteristics for collision prevention at the same time.

However, like the above POM material and special fluorine-based resin material, such a molded body is very costly, as compared to adhesives, etc., and furthermore is difficult to accurately mount on the lens holder.

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